Formation, evolution and thermal stability of interstitial clusters in ion implanted c-Si

The increasing knowledge on the evolution, upon annealing, of the defects generated during ion implantation in crystalline Si helps scientists in the understanding and modelling many phenomena such as transient enhanced diffusion of dopants an extended defect evolution. Nevertheless, it is not fully clear how point-like defects agglomerate forming defect clusters and how they evolve into extended defects. Aim of this work is to provide an interpretation of damage evolution in ion implanted Si using optical, electrical and structural measurements. Low temperature (300-500degreesC) annealing, causes the formation of I-type point-like defects. Annealing at intermediate temperatures (550-650degreesC) produces the formation of I-clusters, experimentally identified observing the effects of the lattice induced strain. High temperatures cause the I-cluster transition to {311} defects. It takes place only if the I supersaturation exceeds a certain value (implantation doses greater than or equal to1 x 10 Si-13/cm(2) in pure Si). Moreover, {311} form only after annealing at T greater than or equal to 650degreesC, thus showing the existence of a temperature threshold. These results suggest the presence of a strong structural rearrangement during the transition.